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Microsurgical chicken thigh model study

I. Background

A. Rationale for study

    1. Microsurgery has become an essential technique in many surgical specialties, such as otolaryngology, plastic surgery, hand surgery, neurosurgery, ophthalmology, maxillofacial surgery, urology, transplantation surgery and gynecology.
    2. Microsurgery is a complex task that requires hand-microscope-eye coordination; respectful handling of the delicate tissues with the microvascular instruments; and steady, fast, and fluid surgical technique.
    3. Microsurgical skills can be improved with learning and practice. The learning curve is difficult when limited to observation and performance in infrequent clinical cases.
    4. Various models can be used to train and assess technical skills and dexterity. The medical profession is under increasing pressure to be able to objectively assess skills and competence.

B. Other models

    • Below are additional models that have been described which are not part of this study. There are currently no active animal model studies for microvascular surgery at UIHC.  We ask that you please do not practice on any of these models until after completing the chicken thigh study.**# Surgical glove / Penrose
      1. Gauze (Demiseren et al. Microsurgical training with surgical gauze: The first step. J Recon Microsurg, 2003 Aug; 19(6): 385-386.)
      2. Foliage leaf  (Kaufman et al. The foliage leaf in microvascular surgery. Microsurg 1984; 5: 57-58.)
      3. “Round the clock” model (Chan et al. The ‘round-the-clock’ training model for assessment and warm-up of microsurgical skills: A validation study. J PRS 2009, 1-6)
      4. Review of models (Chan et al. Validation of microsurgical models in microsurgery training and competence: a review. Microsurgery 27: 494-499, 2007.

II. Chicken thigh model

  • The ischiatic artery leaves the pelvis through the ischial foramen and enters the thigh on the medial side of the femur, where it lies together with the ischiatic nerve and vein covered by the iliotibialis and the iliofibularis muscles. The ischiatic nerve consists of the adherent fascicles of the fibular and tibial nerve. 

III. Microvascular Objective Structured Assessment of Technical Skill (OSATS)

  1. The OSATS is a validated global rating scale for assessing technical competence. A microvascular version was created through collaboration of three experienced microvascular surgeons. It consists of a task-specific score checklist, and a global rating scale.
  2. Click to download a copy of the microvascular OSATS.

II. Instructions

  1. Preparation
    1. If you are not participating in an organized study day:
      1. Contact Grace Nimmons or Nitin Pagedar at least 24 hours in advance so that a chicken specimen can be prepared for you
      2. Pick up study equipment. This will include:
        1. study completion checklist
        2. chicken thigh 
        3. microvascular instrument tray. Click here for information about the instruments in the set.
        4. suture (8-0 or 9-0 nylon)
        5. saline for re-wetting tissue (may also use water)
        6. blue chux absorbent pad
    2. On the Microvascular Anastomotic Techniques protocol, read the Arterial Anastomosis description and watch the video.
      1. You will perform a "back-wall first" anastomosis as shown for this study
  2. Equipment setup
    1. Place the chicken thigh on the blue chux and position the operating microscope to your comfort. Position your equipment as desired. Note that you may need to periodically moisten the tissues by dripping saline/water onto the chicken.
    2. Identify your chicken thigh ischiatic artery.
      1. Limited dissection just around the area of anastomosis is recommended, as it will be more difficult to control the artery if it is entirely separated from the surrounding tissue.
    3. Make an incision through the artery to create two ends for anastomosis. (picture)
  3. Anastomosis
    1. Start video recording on the microscope.
    2. You will perform TWO end-to-end anastomoses of the chicken ischiatic artery
      1. First anastomosis: Use any method you like
      2. Second anastomosis: Use the "back-wall first" technique shown on the Microvascular Anastomotic Techniques protocol
      3. Between your first and second anastomosis, you will need to make another incision at another site along the artery
    3. When you have completed the anastomosis, turn off the video recording. Save the video recording.
  4. Study completion (checklist)
    1. Place your chicken back into the bag and label with your subject ID
    2. Rinse and replace the microvascular instruments into the tray. Dispose suture needle appropriately.
    3. Return instruments and place chicken thigh to the "Completed" section of the study refrigerator.
    4. Complete the study questionaire by clicking here. You will need to enter your chicken ID code.

III. References

Nimmons GL, Chang KE, Funk GF, Shonka DC, Pagedar NA. Validation of a task-specific scoring system for amicrovascularsurgery simulation model. Laryngoscope 2012 Oct;122(10):2164-8




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